You have several good options
Yes you can use blitzsafe (VAGguy gave a link that includes these and other options). One model is made to easily connect in your trunk and you need to route the ipod jack to the front seat. Another is made to connect to the back of the radio but you have to remove the radio. Blitzsafe is the cheapest quality solution I am aware of that will hardwire your Ipod to your stock stereo.
You can also use something like a USAspec model that is more money but has more features (
http://www.usaspec.com/ipod.html). It should also be plug-and-play after you remove the stereo to attach it.
I don't remember all the pros and cons of each solution, but after I considered these options I decided to pay $140 (with $20 coupon) for a top quality Kenwood radio/CD player that also plugs in to an ipod and will charge it, play it, and show song information on it. If you buy a car stereo from Crutchfield, they include all you need to install it to your car and instructions. It's no more work than installing the other solutions as you have to pull out the radio either way (which is easy). All I lost is the stereo controls on the steering wheel. A well laid out stereo is so easy to use that losing the steering wheel function did not matter to me. I gained more power, better sound, better radio reception, more features, and of course the ipod connection that also charges the ipod. I can also add HD Radio, Satellite Radio, and Bluetooth to the Kenwood (though either would approximately double the cost).